Method and device for sending uplink burst data in passive optical network system

ABSTRACT

A method for sending uplink burst data in a passive optical network (PON) system includes: sending a synchronization pattern of the uplink burst data, the synchronization pattern being of a length, which is an integer multiple of 66 bits, and being formed by connection of 66-bit unit gene blocks; sending a burst delimiter (BD) of the uplink burst data; sending a forward error correction (FEC)-protected data in the uplink burst data; and sending an end of burst (EOB) delimiter of the uplink burst data. The technical solutions in the embodiments allow the use of a less complex equalizer at the reception end of a high-speed PON system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application No.12/973,639, filed on Dec. 20, 2010, which is a continuation ofInternational Application No. PCT/CN2009/072290, filed on Jun. 16, 2009.The International Application claims priority to Chinese PatentApplication No. 200810068007.1, filed on Jun. 19, 2008, and ChinesePatent Application No. 200910008103.1, filed on Mar. 2, 2009, andInternational Application No. PCT/CN2008/073140, filed on Nov. 21, 2008.The afore-mentioned patent applications are hereby incorporated byreference in their entireties.

TECHNICAL FIELD

The present invention relates to the field of Passive Optical Network(PON) technologies, and in particular to a method and device for sendinguplink burst data in a PON.

BACKGROUND

The PON becomes a perfect optical access technology because of itsadvantages of being easy to maintain, a high bandwidth, a low cost,etc., which is an ideal physical platform to which various services ofvoice, data, video, etc., gain an integrated access through a singleplatform. The PON technology is an optical fiber access technology ofpoint-to-multipoint (P2MP). The PON including an optical line terminal(OLT), an optical network unit (ONU) and an optical distribution network(ODN) takes advantage of a passive splitter/coupler in the ODN todispense with an element capable of amplification and relaying.

Due to the use of a point-to-multipoint topology for the PON, apoint-to-multipoint multiple access protocol has to be adopted to enablenumerous ONUs to share the OLT and an optical fiber backbone. Asstipulated in the PON system, the direction of data from the OLT to theONU is referred to as the downlink direction and the direction from theONU to the OLT is referred to as the uplink direction. Currently, thewidely applied uplink and downlink transmission modes of the PON systeminvolve the use of a broadcast mode of time division multiplexing (TDM)in the PON downlink and the use of an access mode of time divisionmultiple access (TDMA) in the uplink.

Unlike the conventional point-to-point consecutive communication mode, amultipoint-to-point burst communication mode is adopted in the PONuplink. The uplink channel is shared in the TDMA access mode for PONuplink transmission. The OLT can allocate different time slots to therespective ONUs, each of which can only transmit its own datainformation block in the timeslot assigned by the OLT.

Because the different ONUs are at different distances from the OLT endin the PON system, signals received at the OLT end from the differentONUs also have different intensities. Therefore upon reception at theOLT of a burst data frame from the ONU, the OLT reception end has toperform an automatic gain control (AGC) and a clock data recovery (CDR)by utilizing a synchronization pattern (a preamble) in the receivedburst frame, and then the OLT can matches a burst delimiter (BD) withthe received burst frame and know from the match the starting locationof data in the received burst frame to thereby receive the data.

A burst frame transmitted in the uplink of the existing PON system isstructured in a way that a binary sequence of “1010 . . . ” (ahexadecimal sequence of “0x55 . . . ”) with alternating zeros and onesis defined as a current synchronization pattern which is used for theOLT to perform the AGC and the clock recovery on a received burst frame.It was identified in practice that the spectrum of the synchronizationpattern signal is concentrated at high frequency components, which mightbe adverse to the use of a less complex equalizer at the OLT receptionend. Furthermore, a frequently transition may result in the incapabilityof an existing peak detector to detect an actual peak of a receivedsignal and hence possibly in degraded sensitivity of a receiver.

SUMMARY

Various embodiments of the present invention provide a method forproviding uplink burst data in a PON system in which spectrum componentof a synchronization pattern are relatively uniformly distributedthroughout the spectrum interval to thereby allow the use of arelatively simple equalizer at the reception end of the high-speed PONsystem.

An embodiment of the present invention provides a method for sendinguplink burst data in a PON system, where the method includes:

sending a synchronization pattern of the uplink burst data, the lengthof the synchronization pattern is an integer multiple of 66 bits and thesynchronization pattern is formed by connecting 66-bit unit gene blocks;

sending a burst delimiter (BD) of the uplink burst data;

sending forward error correction (FEC) protected data in the uplinkburst data; and

sending an end of burst (EOB) delimiter of the uplink burst data.

Also an embodiment of the present invention further provides a devicefor providing uplink burst data in a PON system, where the deviceincludes:

a unit adapted to provide a synchronization pattern of the uplink burstdata, the length of the synchronization pattern is an integer multipleof 66 bits and the synchronization pattern is formed by connecting66-bit unit gene blocks;

a unit adapted to provide a BD of the uplink burst data;

a unit adapted to provide FEC-protected data in the uplink burst data;and

a unit adapted to provide an EOB delimiter of the uplink burst data.

Furthermore the present invention further provides a signal including abit stream, the signal being uplink burst data in a PON system, in whichthe signal includes a synchronization pattern, a BD, FEC-protected dataand an EOB delimiter, which are formed by end-to-end connection of66-bit unit gene blocks, and the signal is of a length which is aninteger multiple of 66 bits.

An embodiment of the present invention further provides a method forsending uplink burst data in a PON, where the method includes:

sending a synchronization pattern of the uplink burst data, the lengthof the synchronization pattern is an integer multiple of 32 bits and thesynchronization pattern is formed by connecting 32-bit unit gene blocks;

sending a burst delimiter BD;

sending a burst overhead, which is adapted to detect bit-error-ratio, anONU identifier, and a real time state report of an ONU;

sending Transmission Convergence overhead; and

sending a payload.

An embodiment of the present invention further provides a device forsending uplink burst data in a PON, where the device includes:

a synchronization pattern sending unit, adapted to send asynchronization pattern of the uplink burst data, the length of thesynchronization pattern is an integer multiple of 32 bits and thesynchronization pattern is formed by connecting 32-bit unit gene blocks;

a BD sending unit, adapted to send a BD;

a burst overhead sending unit, adapted to send a burst overhead, whichis adapted to detect bit-error-ratio, an optical network unit (ONU)identifier, and a real time state report of an ONU;

a transmission convergence overhead sending unit, adapted to send atransmission convergence overhead; and

a GTC payload sending unit, adapted to send a payload.

An embodiment of the present invention provides a signal consisting of abit stream, where the signal includes:

a synchronization pattern, being of a length, the length of thesynchronization pattern is an integer multiple of 32 bits and thesynchronization pattern is formed by connecting 32-bit unit gene blocks,

a burst delimiter (BD),

a burst overhead, adapted to detect bit-error-ratio, an network unit(ONU) identifier, and a real time state report of an ONU,

a transmission convergence overhead, and

a payload.

With the uplink/downlink burst data designed in the embodiments of theinvention, spectrum components of its synchronization pattern arerelatively uniformly distributed throughout the spectrum interval tothereby allow the use of a less complex equalizer at the reception endof the high-speed PON system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a structure of burst data transmitted in the uplinkaccording to an embodiment of the invention;

FIG. 2 illustrates gene blocks of the synchronization pattern accordingto an embodiment of the present invention;

FIG. 3 illustrates a diagram of a change of contents in anfirst-in-first-out (FIFO) queue according to an embodiment of thepresent invention;

FIG. 4 is a schematic process flow diagram which illustrates a methodfor sending uplink burst data in a PON system according to an embodimentof the present invention;

FIG. 5 illustrates a spectrum diagram of a synchronization patterngenerated from end-to-end connection of the gene 1;

FIG. 6 illustrates a block diagram of a device for providing uplinkburst data in a PON system according to an embodiment of the presentinvention;

FIG. 7 illustrates a structure of burst data transmitted in the uplinkaccording to a second embodiment of the present invention;

FIG. 8 is a process flow diagram which illustrates a method for sendinguplink burst data according to the second embodiment of the presentinvention;

FIG. 9 illustrates a spectrum diagram of the gene 10; and

FIG. 10 illustrates a block diagram of a device for sending uplink burstdata according to the second embodiment of the present invention.

DETAILED DESCRIPTION

The technical solutions in the embodiments of the present invention willbe described below clearly and fully with reference to the drawings inthe embodiments of the present invention. Evidently, the describedembodiments are only a part but not exhaustive of embodiments of thepresent invention. Any other embodiments which will occur to thoseordinarily skilled in the art in light of the embodiments in the presentinvention here without any inventive effort shall fall within the scopeof the present invention.

A technical solution will be described in an embodiment of the presentinvention taking a 10G Ethernet Passive Optical Network (10G EPON)system as an example. In the structure of burst data transmitted in theuplink according to the embodiment of the present invention asillustrated in FIG. 1, the uplink burst data transmitted from an ONUinclude a Synchronization pattern, a BD, an FEC-protected Ethernet dataand an EOB delimiter. In particular, the synchronization pattern and theBD are not protected with FEC encoding, and FEC codewords, i.e. theFEC-protected Ethernet data, follow the BD. The BD indicates the startof the FEC-protected data in the burst. The synchronization pattern isused for an OLT to perform an AGC and a clock recovery on a receivedburst frame.

The synchronization pattern designed in an embodiment of the presentinvention includes an extended 66-bit gene block. FIG. 2 presents a setof gene blocks, i.e. elementary gene blocks, for generation of thesynchronization pattern described in the embodiment of the presentinvention. The elementary gene blocks illustrated in FIG. 2 aresubjected to an inversion or mirroring or cyclic shift process, whichresults in gene blocks of a new design synchronization pattern. Thesynchronization pattern designed in the embodiment of the presentinvention consists of these gene blocks connected end-to-end.

More gene blocks for generation of the synchronization pattern describedin the present invention can be derived from the elementary gene blocksin FIG. 2. For example, inversion of the elementary gene block 1 resultsin the following gene block:

010000001011111101111001110101100001011100011011010010001 001100101;

A mirror process on the elementary gene block 1 results in the followinggene block:

010110011011101101001001110001011110010100011000010000001 011111101;

The mirroring process can be taken for as a reversion process, forexample, the mirroring process on ABCD results in DCBA.

A cyclic shift on the elementary gene block 1 results in the followinggene block:

010111111010000001000011000101001111010001110010010110111 011001101.

The above process is a one-bit cyclic shift process. Acyclic shiftprocess of any number of bits is possible in practice.

In the same way, more gene blocks can be derived from an inversion,mirroring or cyclic shift on the elementary gene blocks presented inFIG. 2. A gene block can still be derived from a cyclic shift on anelementary gene block that has been subjected to an inversion ormirroring process.

An elementary gene block may include:

101111110100000010000110001010011110100011100100101101110 110011010 or

101010011110100011100100101101110110011010101011111000001 000011000 or

100110011110100011100100101101110110011010101011111000001 000011000 or

100101011110100011100100101101110110011010101011111000001 000011000 or

101000111101000111001001011101110110011010101011111000001 000011000 or

101001111010001110010010101011101100110101011111011000001 000011000 or

101001111010001110010010110111011001101010011111011000001 000011000 or

101001111010000111001001011011110110011010101111110000001 000011000 or

101001111010001110010010110111011001101010111111010000001 000011000.

The elementary gene blocks presented in FIG. 2 and the gene blocksderived from the elementary gene blocks are characterized in common asthe following:

The synchronization pattern designed according to the embodiment of thepresent invention is of a length which is an integer multiple of 66bits, and the synchronization pattern includes end-to-end connection ofa 66-bit gene block.

The synchronization pattern designed according to the embodiment of thepresent invention is a direct current balance sequence with the same runlengths of zeros and ones, where the maximum run length is 6.

The on/off of the laser at a transmission end shall be controlled by theONU in the existing 10G-EPON system. When the ONU has no data fortransmission, the laser of the ONU shall be turned off in order to avoidan influence on transmission from an adjacent ONU. The switch of thelaser is controlled with a data detector, and the laser is turned on bythe ONU when the data detector detects arrival of data for transmission.

A method for providing uplink burst data will be introduced with respectto a change of contents in an FIFO queue according to an embodiment ofthe present invention in FIG. 3.

The FIFO queue before and after substitution can be represented in thetable below:

FIFO serial Value before Value after number substitution substitutionDescriptions N-1 Scrambled Scrambled The value is scrambled IDLE IDLEIDLE at the end of the original FIFO queue N-2 Scrambled Scrambled Thevalue is scrambled IDLE IDLE IDLE at the end of the original FIFO queueN-3 Scrambled BD Substituted by the BD IDLE N-4 Scrambled 0x 4 BF 40 18Substituted by the 66-bit IDLE E5 C5 49 BB 59 gene block of thesynchronization pattern . . . . . . . . . The same as the above 1Scrambled 0x 4 BF 40 18 The same as the above IDLE E5 C5 49 BB 59 0Scrambled 0x 4 BF 40 18 The same as the above IDLE E5 C5 49 BB 59 (Thevalues after substitution are represented in a hexadecimal form)

The serial number 0 of the FIFO queue denotes the start of the queue,and N-1 denotes the end of the queue. The values before and aftersubstitution each are in units of block, i.e. an integer multiple of 66bits.

When data for transmission arrives at the data detector of the ONU,contents of the two FIFO blocks [N-1] and [N-2] at the end of the queue(IDLE) keep unchanged, contents of the FIFO block [N-3] are substitutedby the BD, and contents of the FIFO blocks [N-4] to [0] are substitutedby the synchronization pattern designed according to the presentinvention. N denotes the length of the queue, which is dependent uponthe synchronization time. Then, the data in the queue is transmitted outsequentially by the rule of FIFO.

Due to the rule of FIFO for the FIFO queue, the synchronization patternof the uplink burst data is firstly provided, for example, thesynchronization pattern includes N-3 blocks of 66-bit genes 1 in FIG. 2according to the embodiment of the present invention, i.e. N-3 blocks of1011111101000000100001100010100111101000111001001011011101100110 10 (ahexadecimal value of 0x 4 BF 40 18 E5 C5 49 BB 59), which are connectedend-to-end. Then the BD of the uplink burst data is provided. ThereafterFEC-protected data in the uplink burst data is provided. Finally the endof BD of the uplink burst data is provided. When the contents in theFIFO queue of the data detector of the ONU are IDLE, the ONUtransmission end will turn off the laser. Transmission of the uplinkburst data is finished.

Evidently, in the above descriptions, the providing, by the ONU, eachpart of the uplink burst data means that the ONU sends each of the partsto the OLT. The parts sent by the ONU in sequence form the uplink burstdata. The parts herein include: the synchronization pattern, the BD, theFEC-protected data, and the EOB delimiter.

Referring to FIG. 4, an embodiment of the present invention provides amethod for providing uplink burst data in a PON system, i.e. a methodfor sending uplink burst data in a PON system, and the method includesthe following steps:

Step 11: sending a synchronization pattern of the uplink burst data, thelength of the synchronization pattern is an integer multiple of 66 bitsand the synchronization pattern is formed by connecting 66-bit unit geneblocks;

Step 12: sending a BD of the uplink burst data;

Step 13: sending an FEC-protected data in the uplink burst data; and

Step 14: sending an EOB delimiter of the uplink burst data.

Thus, the uplink burst data generated in the embodiment is a signalincludes a bit stream, and the signal includes the synchronizationpattern, the BD, the FEC-protected data and the end of BD, formed fromend-to-end connection of 66-bit unit gene blocks, and is of a lengthwhich is an integer multiple of 66 bits. The synchronization pattern isa direct current balance sequence with the same run lengths of zeros andones in the binary codes, where the maximum run length is 6. The 66-bitgene block in use can be any elementary genes block illustrated in FIG.2 or be derived from an inversion or mirroring or cyclic shift processon the elementary gene block, and the gene block can still be derivedfrom a cyclic shift on the elementary gene block that has been subjectedto an inversion or mirroring process.

After the OLT reception end receives the burst data transmitted from theONU, the OLT reception end can perform a clock recovery and an AGC onthe received data by utilizing transition between zeros and ones of theburst synchronization pattern in the burst data frame.

The synchronization pattern designed in the embodiment of the presentinvention is a direct current balance sequence with the same run lengthsof zeros and ones, where the maximum run length is 6, so that a peakdetector at the reception end can detect an approximately 100% peaklevel of the received signal.

The spectrum of the synchronization pattern designed in the embodimentof the present invention is relatively uniformly distributed throughoutthe spectrum interval to thereby allow the use of a less complexequalizer at the OLT reception end. FIG. 5 illustrates a spectrumdiagram of the synchronization pattern generated from end-to-endconnection of the genes 1. As can be apparent from FIG. 5, the spectrumof the synchronization pattern of the uplink burst data in theembodiment appears as the solid line which is relatively uniformthroughout the spectrum interval. The dotted lines represent thespectrum diagram of the synchronization pattern in the prior art inwhich spectrum components are concentrated at high frequency. As can beseen from the figure, a good effect has been achieved in the embodiment.

Also an embodiment of the present invention provides a device forproviding uplink burst data in a PON system as illustrated in FIG. 6,where the device 5 includes:

a unit 501 adapted to provide a synchronization pattern of the uplinkburst data, the length of the synchronization pattern is an integermultiple of 66 bits and the synchronization pattern is formed byconnecting 66-bit unit gene blocks;

a unit 502 adapted to provide a BD of the uplink burst data;

a unit 503 adapted to provide an FEC-protected data in the uplink burstdata; and

a unit 504 adapted to provide an EOB delimiter of the uplink burst data.

In particular, the synchronization pattern provided by the unit adaptedto provide the synchronization pattern of the uplink burst data is adirect current balance sequence with the same run lengths of zeros andones in its binary codes, where the maximum run length is 6. The 66-bitgene block in use can be any elementary gene block illustrated in FIG. 2or be derived from an inversion or mirroring or cyclic shift process onthe elementary gene block, and the gene block can still be derived froma cyclic shift on the elementary gene block that has been subjected toan inversion or mirroring process.

A technical solution will be described in a second embodiment of thepresent invention taking a GPON system as an example. In the structureof burst data transmitted in the uplink according to the secondembodiment of the present invention as illustrated in FIG. 7. The uplinkburst data transmitted from an ONU include a Physical Layer Overheadupstream (PLOu), a Gigabit-Capable Passive Optical Network (GPON)Transmission Convergence (GTC) overhead, and a GTC payload. The PLOuincludes a Synchronization pattern, a BD, and a burst overhead. TheSynchronization pattern and BD are set by parameters ofUpstream_Overhead. The Upstream_Overhead is sent by an OLT. Thesynchronization pattern is used for the OLT to perform an AGC and aclock recovery on a received burst frame.

In one embodiment of the present invention disclose a method for sendinguplink burst data in a PON, as illustrated in FIG. 8.

In step S101, a synchronization pattern of the uplink burst data issent, the length of the synchronization pattern is an integer multipleof 32 bits and the synchronization pattern is formed by connecting32-bit unit gene blocks.

The synchronization pattern designed in an embodiment of the presentinvention includes an extended 32-bit gene block. Chart 1 presents a setof gene blocks, i.e. elementary gene blocks, for generation of thesynchronization pattern described in the embodiment of the presentinvention. The elementary gene blocks illustrated in Chart 1 aresubjected to an inversion or mirroring or cyclic shift process, whichresults in gene blocks of a new design synchronization pattern. Thesynchronization pattern designed in the embodiment of the presentinvention includes these gene block connected end-to-end.

CHART 1 Gene blocks of the synchronization pattern (32-bit) 32-bit geneblock Gene 10 10111011010100100001111000100110 Gene 1100010011010011110111010000101011 Gene 1211010011011100101011110100010000 Gene 1311110001001101011101101010010000 Gene 1410111011110010110010001101010000 Gene 1510101100010011010011110111010000 Gene 1610001011110101001110110010110000 Gene 1711110110101001000101001101110000 Gene 1810010101101110101100100011110000 Gene 1911101100101000100101011011110000

More gene blocks for generation of the synchronization pattern describedin the present invention can be derived from the elementary gene blocksin Chart 1. For example, inversion of the elementary gene block 10results in the following gene block: 01000100101011011110000111011001

A mirror process on the elementary gene block 10 results in thefollowing gene block: 01100100011110000100101011011101;

The mirroring process can be taken for as a reversion process, forexample, the mirroring process on ABCD results in DCBA.

A cyclic shift on the elementary gene block 10 results in the followinggene block: 11101101010010000111100010011010.

The above process is a two-bit cyclic shift process. A cyclic shiftprocess of any number of bits is possible in practice.

In the same way, more gene blocks can be derived from an inversion,mirroring or cyclic shift on the elementary gene blocks presented inChart 1. A gene block can still be derived from a cyclic shift on anelementary gene block that has been subjected to an inversion ormirroring process.

The elementary gene blocks presented in Chart 1 and the gene blocksderived from the elementary gene blocks are characterized in common asthe following:

The synchronization pattern designed according to the embodiment of thepresent invention is of a length which is an integer multiple of 32bits, and the synchronization pattern consists of end-to-end connectionof a 32-bit gene block.

The synchronization pattern designed according to the embodiment of thepresent invention is a direct current balance sequence with the same runlengths of zeros and ones, where the maximum run length is 4.

The OLT according to the system parameters choose a gene block fromchart 1. In an example use a 32-bit sequence like 0x BB52 1E26, i.e.1011 1011 0101 0010 0001 1110 0010 0110. An OLT transmission end definesthe sequence in Upstream_Overhead, and the Upstream_Overhead pre-definedby the OLT is embedded in downstream PLOAMd. The ONU sends thesynchronization pattern of the uplink burst data according to thesynchronization pattern in the Upstream_Overhead in the received PLOAMd.The sent synchronization pattern according to the embodiment of thepresent invention is a direct current balance sequence with the same runlengths of zeros and ones, where the maximum run length is 4.

In step S102, a BD is sent.

In step S103, a burst overhead is sent. The burst overhead is adapted todetect bit-error-ratio, an identifier ONU-ID, and a real time statereport of an ONU.

In step S104, a transmission convergence overhead is sent.

In step S105, a payload is sent.

The sending of the uplink burst data is finished, and a signal consistsof a bit stream is generated at the same time.

After the OLT reception end receives the burst data transmitted from theONU, the OLT reception end can perform a clock recovery and an AGC onthe received data by utilizing transition between zeros and ones of theburst synchronization pattern in the burst data frame.

The spectrum of the synchronization pattern designed in the embodimentof the present invention is relatively uniformly distributed throughoutthe spectrum interval to thereby allow the use of a less complexequalizer at the OLT reception end. FIG. 9 illustrates a spectrumdiagram of the genes 10 from Chart 1 according to the embodiment of thepresent invention. As can be apparent from FIG. 9, the spectrum of thesynchronization pattern of the uplink burst data in the embodimentappears as the solid line which is relatively uniform throughout thespectrum interval. The dotted lines represent the spectrum diagram ofthe synchronization pattern in the prior art in which spectrumcomponents are concentrated at high frequency. As can be seen from theFIG. 9, a good effect has been achieved in the embodiment. According tothe embodiment of the present invention, a peak detector at thereception end can detect an approximately 100% peak level of thereceived signal.

Also the second embodiment of the present invention provides a devicefor providing uplink burst data in a PON system as illustrated in FIG.10, the device 90 includes: a synchronization pattern sending unit 901,a BD sending unit 902, a burst overhead sending unit 903, a transmissionconvergence overhead sending unit 904, and a payload sending unit 905.

The synchronization pattern sending unit 901 is adapted to send asynchronization pattern. The length of the synchronization pattern is aninteger multiple of 32 bits and the synchronization pattern is formed byconnecting 32-bit unit gene blocks.

The synchronization pattern sent by the synchronization pattern sendingunit 901 is a direct current balance sequence with the same run lengthsof zeros and ones, where the maximum run length is 4. The 32-bit geneblock in use can be any elementary genes block illustrated in Chart 1 orbe derived from an inversion or mirroring or cyclic shift process on theelementary gene block, and the gene block can still be derived from acyclic shift on the elementary gene block that has been subjected to aninversion or mirroring process.

The BD sending unit 902 is adapted to send a BD.

The burst overhead sending unit 903 is adapted to send a burst overhead,and the burst overhead is adapted to detect bit-error-ratio, anidentifier ONU-ID, and a real-time state report of an ONU.

The transmission convergence overhead sending unit 904 is adapted tosend a transmission convergence overhead.

A payload sending unit 905 is adapted to send a payload.

The spectrum of the synchronization pattern designed by the deviceaccording to the embodiment of the present invention is relativelyuniformly distributed throughout the spectrum interval to thereby allowthe use of a less complex equalizer at the reception end of a high-speedPON system.

The foregoing descriptions are merely illustrative of the severalembodiments of the present invention, and those skilled in the art canmake various modifications or variations of the present invention inlight of the disclosure of the application without departing from thespirit and scope of the present invention.

1. A method for sending uplink burst data in a passive optical network(PON) system, the method comprising: sending a synchronization patternof the uplink burst data, wherein the length of the synchronizationpattern is an integer multiple of 66 bits and the synchronizationpattern is formed by connecting 66-bit unit gene blocks, wherein the66-bit gene block that is represented in a binary form is:1011111101000000100001100010100111101000111001001011011101100 11010; oris derived from an inversion, mirroring or cyclic shift on the geneblock or from a cyclic shift on the gene block that has been subjectedto an inversion or mirroring process; sending a burst delimiter (BD) ofthe uplink burst data; sending forward error correction (FEC) protecteddata in the uplink burst data; and sending an end of burst (EOB)delimiter of the uplink burst data.
 2. The method according to claim 1,wherein the synchronization pattern is a direct current balance sequencewith the same run lengths of zeros and ones in its binary codes, and themaximum run length is
 6. 3. A device for providing uplink burst data ina passive optical network (PON) system, the device comprising: a unitadapted to provide a synchronization pattern of the uplink burst data,wherein the length of the synchronization pattern is an integer multipleof 66 bits and the synchronization pattern is formed by connecting66-bit unit gene blocks, wherein the 66-bit gene block, which providedby the unit adapted to provide the synchronization pattern of the uplinkburst data, that is represented in a binary form is:1011111101000000100001100010100111101000111001001011011101100 11010; oris derived from an inversion, mirroring or cyclic shift on the geneblock or from a cyclic shift on the gene block that has been subjectedto an inversion or mirroring process; a unit adapted to provide a burstdelimiter (BD) of the uplink burst data; a unit adapted to provideforward error correction (FEC) -protected data in the uplink burst data;and a unit adapted to provide an end of burst (EOB) delimiter of theuplink burst data.
 4. The device according to claim 3, wherein thesynchronization pattern is a direct current balance sequence with thesame run lengths of zeros and ones in its binary codes, and the maximumrun length is 6.